WASHINGTON -- The White House said a new “expeditionary tracking force” being deployed to Iraq will number around 200 troops, as the United States expands its fight against Islamic State (IS) militants there and in Syria.

White House spokesman Josh Earnest also told reporters on December 2 that the additional deployment had the backing of Iraq’s government, which a day earlier had pointedly said it opposed the force.

Earnest tried to distinguish between the new force аnd the 100,000-strong force that invaded and occupied Iraq in 2003.

“This is consistent with what we’ve been doing in Iraq and Syria in the past. It is also an intensification that...involves about 200 United States military personnel,” he said. “That certainly stands in contrast to the more than 100,000 U.S. troops that were on the ground in Iraq and were sent there by the previous administration.”

The new force, initially announced December 1 by Defense Secretary Ash Carter, is the latest move by Washington to bolster Iraq’s efforts to battle IS militants and improve its results against the group.

Some 3,500 U.S. troops are already stationed in Iraq in various capacities, and U.S. forces have been stepping up its tactical, battlefield assistance to Iraqi Kurdish forces in particular, who recently took back the strategic northern city of Sinjar from Islamic State fighters.

Some 50 U.S. special operations troops are also being deployed to work with Kurdish and Syrian Arab forces fighting against IS forces.

In testimony before Congress on December 1, Carter said the mission for the expanded force in Iraq would include conducting raids, rescuing hostages, gathering intelligence, and trying to capture or kill IS leaders.

He also said the force would be authorized to conduct raids in neighboring Syria, where Islamic State fighters have also seized large chunks of territory.

Carter’s announcement was met with public opposition in Baghdad, adding to confusion about the scope and authority of the new force.

"The Iraqi government stresses that any military operation or the deployment of any foreign forces -- special or not -- in any place in Iraq cannot happen without its approval and coordination and full respect of Iraqi sovereignty," Iraqi Prime Minister Haidar al-Abadi said in a statement released December 1.

Earlier on December 2, Colonel Steve Warren, a Baghdad-based spokesman for U.S. operations in Iraq, gave a smaller figure for the new force -- around 100.

He also said only a small portion of the troops would be “trigger-pullers” -- shooting or firing on targets.

Most, he said, would be doing advising, communications, and similar battlefield assistance.

The discrepancy between the figures given by Warren and Earnest couldn’t be explained and a message left with White House officials wasn’t immediately returned.

Warren also said the new force had been discussed with Abadi.

"We've been talking about this with the prime minister for weeks," Warren said, speaking by teleconference from Baghdad.

U.S. Secretary of State John Kerry, speaking in Brussels at a meeting of NATO foreign ministers, also emphasized that U.S. officials had consulted with Iraq’s government on the new force.

“We have full and total respect and work with, for Prime Minister Abadi’s leadership. We work very closely with him,” Kerry told reporters. “And we strongly support his efforts to restore Iraq’s sovereignty and territorial integrity against ISIL attacks, and I can assure you that as the plans are developed, it will be in full consultation and with the full consent of the Iraqi government.”